Uranium

What is uranium?
Where is uranium found?
Where are uranium deposits located?
When did uranium mining begin in Canada?
What is the history of uranium?

What is uranium?

In its pure form, uranium is a silvery white metal of very high density, more dense even than lead. Uranium can take many chemical forms, but in nature it is generally found as an oxide (in combination with oxygen). Triuranium octoxide (U₃O₈) is the most stable form of uranium oxide and is the form most commonly found in nature.

Where is uranium found?

Uranium is one of the most abundant elements found in the Earth's crust. It can be found almost everywhere in soil and rock, in rivers and oceans. Traces of uranium are even found in food and human tissue. However, concentrated uranium ores are found in just a few places, usually in hard rock or sandstone.

The concentration of uranium varies according to the substances it is mixed with and the places where it is found. For example, when uranium is mixed with granite that covers 60% of the Earth's crust, there are approximately four parts of uranium per million, i.e. 999,996 parts of granite and four parts of uranium.

Concentrations of uranium that are economic to mine are considered ore. Uranium is present in low concentrations in many rocks and bodies of water, but extraction is only economically viable from richer deposits. The decision to mine is a function of many factors including extraction method, market prices and social and environmental considerations.

Where are uranium deposits located?

Uranium deposits are found all over the world. The largest deposits of uranium are found in Australia, Kazakhstan and Canada. High-grade deposits are only found in Canada. The following illustration shows known conventional resources of uranium.

When did uranium mining begin in Canada?

Canada's uranium journey began in 1931 at Great Bear Lake in the Northwest Territories where veteran prospector Gilbert Labine discovered the country's first uranium deposit. Labine's discovery gave birth to Eldorado Nuclear Limited, a forerunner of Cameco Corporation. Today, Cameco dominates the uranium market as the majority owner of the world's largest and highest-grade uranium deposits.

For more information, go to Uranium in Saskatchewan

What is the history of uranium?

Uranium was discovered in 1789 by German chemist Martin Klaproth while analysing mineral samples from the Joachimsal silver mines in the present day Czech Republic. Apart from its value to chemists, the only significant use for uranium throughout the 1800s was to colour glass and ceramics. Uranium compounds were used to give vases and decorative glassware a yellow-green colour. Ceramic glazes ranging from orange to bright red were used on items as varied as household crockery and architectural decorations.

Uranium's radioactive properties were not noticed until 1896. French scientist Henri Becquerel did not realize the full significance of his discovery, but one of his students, Marie Curie, correctly interpreted his results and chose the name radioactivity for the new phenomenon. Working with her husband Pierre, Marie Curie went on to discover another new element, radium, in 1898. The Curies had to use tonnes of uranium ore to obtain even a fraction of a gram of this new element. Radium was felt to be a miracle cure for cancer and commanded prices as high as $75,000 per ounce until the bottom fell out of the market in the late 1930s.

Demand for radium led to a rapid expansion in the mining of uranium ore in the early 1900s. New discoveries were made in the US, Australia, Portugal, the Belgian Congo (now Zaire) and Canada.

After the Curies' first work with radioactive materials, many scientists around the world began to study uranium, trying to discover its atomic secrets. In 1939, the first proven nuclear fission was performed by Otto Hahn in Germany. By this time the world was on the edge of war and military secrecy quickly surrounded the work of atomic scientists. A team led by Enrico Fermi built the first nuclear reactor (known as an "atomic pile") in great secrecy at the University of Chicago. This pile achieved the first controlled nuclear reaction in 1942. The US, fearful that Germany would be the first to develop an atomic weapon, assembled a team of leading nuclear scientists from several countries. Their work, known as the Manhattan Project, resulted in the first nuclear explosion at the Trinity test site in New Mexico in July 1945. The world became aware of the enormous destructive power of nuclear weapons a month later when the Japanese cities of Hiroshima and Nagasaki were destroyed.

After the war ended, attention quickly turned to developing the peaceful uses of nuclear energy. The first practical use of nuclear power was in 1951, when an experimental nuclear reactor at a US research centre in Idaho Falls lit four ordinary light bulbs. In 1957, the first full-scale US nuclear power plant went into service at Shippingport, Pennsylvania. It had a generating capacity of 60 megawatts, a small amount by today's standards.

Meanwhile several other countries were also building reactors. In 1954, the world's first commercial reactor produced power in Obninsk, Russia. Britain's Calder Hall started in 1956 and was the world's first industrial-scale nuclear power station. The French nuclear program had a slower start after the war, but generated its first electricity with a reactor at Marcoule in 1956. Canada and Sweden also succeeded in independently generating nuclear electricity, in 1962 and 1964 respectively.

The nuclear industries of these countries grew rapidly during the 1960s and 1970s. The first export orders for nuclear power reactors, awarded by Italy in 1958, were followed by the spread of nuclear electricity generation to many other countries, including the former West Germany, Switzerland, Spain, Belgium, Finland and Japan. The Soviet Union exported reactors to Eastern European countries, including East Germany, Czechoslovakia, Bulgaria and Hungary. Many of these countries developed their own nuclear expertise, leading to the development of today's international nuclear industry.

The world's major source of uranium until the early 1950s was in the Belgian Congo. Later, to meet the requirements of the fast-growing nuclear industry, uranium mining was expanded in the US, Canada, France, Australia, and Africa. Today, Canada produces the largest share of uranium from mines (about one-third of world supply), followed by Australia (one-fifth).